It's nothing quite like what you're looking for (i.e., an all-in-one, comprehensive and pedagogically sound guide to using the Vocaloid Editor), but here are some resources I've accumulated and found, to varying extents, useful:

"Using the Parameters" page on the Vocaloid Wiki: http://vocaloid.wikia.com/wiki/Using_the_Parameters

If you go back to the page, does it show up, by any chance? The posts seem to auto-save periodically, so if you go back it might still be there in the editor. At least that's how it was when I was working on a PM.